(a) Field of the Invention
The present invention relates to a drowsy driver warning system and, more particularly, to the driver's drowsiness detection method for determining whether driver is drowsy or not.
(b) Description of the Related Art
Recently, much research and development has been conducted on the advanced safety vehicle (ASV) for preventing road accidents and minimizing damage when collisions occur. The basic concept of the ASV is a safety-guaranteed and accident-preventive vehicle. To achieve these objectives, many safety technologies are adapted in the ASV. These technologies includes a drowsy driving warning system, a nighttime pedestrian monitoring and warning system, a fire alarm system, and so on.
Among them, the drowsy driving warning system helps prevent accidents caused by a drowsy driver at the wheel by means of sounding an alarm, shaking the seat, increasing the audio volume, or emitting a strong stimulating gas. Thus, prior to activating an alarm, there is needed to detect the driver's condition as to whether or not he is drowsy, by analyzing his face image and signals from electrical switches such as a brake switch, a directional signal switch, a wiper switch, and so on.
In such a drowsy driving warning system, image-processing technology is used to analyze the driver's face image, particularly his eyes, taken with a charge-coupled device (CCD) camera. If the driver's eyes are frequently kept closed over a predetermined period, a drowsiness detection unit determines that the driver is drowsy so as to sound an alarm.
In the prior art, since the driver's condition is determined by simple drowsiness factor on the basis of the duration and frequency of the closing of the driver's eyes, the reliability of the driver's condition assessment deteriorates if there is noise in the driver's face image data.